Electromagnetic torque and reactive torque control of induction motor drives to improve vehicle variable flux operation and torque response

This paper investigates the decoupling and fast torque response for induction motor drives during vehicle operation with variable flux. A torque control method considering flux transient information is proposed, which takes the electromagnetic torque and reactive torque as state variables for modeling and feedback linearization control. Since the electromagnetic torque is aligned with the active power, and the reactive torque is aligned with the reactive power and perpendicular to the electromagnetic torque, the stator dq-axis current control of the field-oriented control (FOC) is replaced by the simultaneous control of the electromagnetic torque and reactive torque. The physical concept of the inner loop changes from the current to the torque, and the modulation signals from the voltage-type to the power-type. This strategy improves the decoupling performance under variable flux, and the fast response capability of the torque. In addition, it eliminates the complex rotation coordinate transformation. A comparative experiment was carried out between the proposed method and the FOC. Both methods have good steady-state performance. However, the proposed method has better torque response and decoupling.